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Salt/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby Tim is lying in his bed. Moby is at Tim's bedside. Tim opens his eyes and sees Moby holding a letter. MOBY: Beep. Tim reads from the typed letter. TIM: Dear Tim, Happy Birthday. You can do whatever movie you want! From, Moby. Aw, thanks, buddy. My own movie, hmmm. I guess I've always wanted to do one on salt. Yeah, I, I know, it may sound random, but salt is one of the most important substances on Earth. An image shows a pile of salt. TIM: All complex beings need salt to survive. Animations and images show someone shaking salt out of a shaker, a deer licking a salt crystal, and a fish in water. TIM: Without salt, our blood wouldn't circulate, our heart wouldn't pump, our nerves wouldn't fire, nothing would work. Images show a vein and an artery, a heart, and nerves. TIM: Because it's so necessary to life, salt has played a big part in human history. Wars have been fought for it, poems written about it, and customs built around it. Images shows symbols representing wars, poems, and customs. MOBY: Beep. TIM: The word salt can mean any number of different compounds, but I'm talking about sodium chloride, or table salt. One molecule of salt is made from a single atom of sodium bonded to a single chlorine atom. An image shows the periodic table of elements. N-a, for salt, and C-l, for chlorine, are called out and their bonded atoms are shown. TIM: In their solid form, the atoms arrange themselves into crystals. An image shows a salt crystal, with a detail showing the atomic structure of the crystal. TIM: Salt is an electrolyte. That means that when it dissolves in water or other liquids, it breaks up into ions, or charged atoms, in this case, positive sodium ions and negative chloride ions. An animation illustrates the sodium chloride molecules, which have positive sodium and negative chloride, dissolving into water and breaking up into ions. TIM: This makes the liquid it's dissolved in a good electrical conductor. MOBY: Beep. TIM: Well, that's the reason salt is so important to complex life forms like humans. See, most of your cells are surrounded by fluids that are rich in electrolytes. Good health depends on a complex balance of electrolytes inside and outside your cells. Cells react to imbalances by releasing or taking in fluids. An animation shows electrolytes in and around cells. TIM: For example, when we get dehydrated, the amount of water in our blood decreases and the sodium concentration increases. An animation shows decreasing water molecules in blood. TIM: The rise in blood sodium triggers cells in the brain to tell us that we're thirsty. Tim is shown drinking a glass of water. TIM: And this is one of the thousands of ways our bodies depend on salt. MOBY: Beep. TIM: Well, our bodies can't store salt, so we need to get it through the food we eat. These days, it's pretty easy to come by, though. In fact, most people have had to watch their salt intake at one time or another. Moby steps away from Tim. TIM: Oh, hey, hey, we're not quite done here. Besides nutrition, people have put salt to all kinds of uses throughout history. It was one of the most popular food preservatives before the invention of refrigeration, because it stops bacterial growth. In fact, it's still used as a preservative to this day. An animation shows a man using salt as a meat preservative. TIM: In some ancient societies, like Rome, salt was used as a form of money. In fact, the Latin word for salt is the root of the word salary. An animation shows two men exchanging a bag of salt. TIM: These days, we use salt for everything from deicing roads to water purification. MOBY: Beep. TIM: Salt is available from large deposits left behind by ancient oceans, and it's dissolved in huge quantities in today's oceans. Harvesting it from the ocean requires the extra step of evaporating the water. Side by side images show a vehicle in a salt mine and a man working in a salt farm. TIM: Through the ages, access to salt deposits has fueled both treaties and wars between countries. An image shows a government official at a meeting holding up a document labeled "Salt Tax." TIM: You could, you could write a world history just by looking at our relationship with salt. Moby places a tray of food before him. TIM: Wow, a birthday breakfast? That's nice. Tim takes a sip of orange juice, but reveals he put salt in his orange juice. TIM: Ugh! You, you put salt in it! Category:BrainPOP Transcripts